A neo 2.2 chip does 2 things
1. Send the SCEA signal
2. Allow you to use the tray opening feature (the EA swap)

For PSone CD-R games
The chips sends the SCEA signal PS2 is happy game plays

For PS2 CD-R
You need a PS2 boot sequence thus the gameshark booting with its TOC when you open the tray the PS2 reads the TOC again but the GS (gameshark) counteracts this and then send the SCEA signal to play the game once you insert it

For PS2 DVD-R
Works similar to CDs but Since you need a DVD TOC it will read on the second tray opening thus the EA method counteracts the TOC reading for the second swap. (Why we need pins 2, 3, 4,5,6 and 7)